U.S. patent number 6,121,213 [Application Number 09/123,345] was granted by the patent office on 2000-09-19 for stable peroxide denture paste.
This patent grant is currently assigned to Block Drug Company, Inc.. Invention is credited to Michael E. Trama, Democrita E. Vergara, Kuo-Chen Yeh.
United States Patent |
6,121,213 |
Vergara , et al. |
September 19, 2000 |
Stable peroxide denture paste
Abstract
A denture cream for cleaning dentures and removable dental
prostheses comprising a peroxide stabilized against chemical
degradation by a combination of a bicarbonate and a phosphate, such
as an alkali monofluorophosphate.
Inventors: |
Vergara; Democrita E. (Nutley,
NJ), Trama; Michael E. (River Vale, NJ), Yeh;
Kuo-Chen (Westfield, NJ) |
Assignee: |
Block Drug Company, Inc.
(Jersey City, NJ)
|
Family
ID: |
22408141 |
Appl.
No.: |
09/123,345 |
Filed: |
July 28, 1998 |
Current U.S.
Class: |
510/116; 424/53;
424/57 |
Current CPC
Class: |
A61K
8/22 (20130101); A61Q 11/02 (20130101); A61K
2800/52 (20130101) |
Current International
Class: |
A61K 007/30 ();
A61K 007/20 (); A61K 007/16 () |
Field of
Search: |
;510/116,117
;424/49,53,57 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Poletto, J.F., & Bernstein, S,. United States Statutory
Invention Registration No. H83 Jul. 1, 1986 pp. 1-26..
|
Primary Examiner: Gupta; Yogendra
Assistant Examiner: Petruncio; John M.
Claims
What is claimed is:
1. A cream formulation for cleaning dentures and other removable
dental prostheses in association with mechanical scrubbing
comprising:
(a) a peroxide in an amount sufficient to provide a cleaning effect
to said cream;
(b) a bicarbonate in a weight ratio to the peroxide of about 10:1
or less; and
(c) a phosphate in a weight ratio to the peroxide of about 1.6:1 or
less; and
wherein said denture cleansing cream formulation is characterized
in having a residual amount of active oxygen of about 80% or more
after one week at 50.degree. C.
2. The cream of claim 1, wherein said peroxide is an alkali
peroxide.
3. The cream of claim 1, wherein said peroxide is a divalent
peroxide.
4. The cream of claim 3, wherein said peroxide is calcium
peroxide.
5. The cream of claim 1, wherein said peroxide comprises from about
0. 1% to about 10% by weight of the cream.
6. The cream of claim 5, wherein said peroxide comprises from about
0.25% to about 5% by weight of the cream.
7. The cream of claim 6, wherein said peroxide comprises from about
0. 5% to about 2.5% by weight of said cream.
8. The cream of claim 1, wherein said bicarbonate is selected from
the group consisting of alkali bicarbonates.
9. The cream of claim 8, wherein said bicarbonate is sodium
bicarbonate.
10. The cream of claim 1, wherein said bicarbonate comprises more
of the denture cream formulation than the peroxide on a weight
basis.
11. The cream of claim 10, wherein said bicarbonate is present in
said cream in a weight ratio to said peroxide from about 2:1 to
about 10:1.
12. The cream of claim 11, wherein said bicarbonate is present in
said cream in a weight ratio to said peroxide from about 2:1 to
about 5:1.
13. The cream of claim 7, wherein said bicarbonate comprises from
about 1% by weight to about 25% by weight of the denture cream.
14. The cream of claim 13, wherein said bicarbonate comprises from
about 1% by weight to about 10% by weight of the denture cream.
15. The cream of claim 14, wherein said bicarbonate comprises about
5% by weight of the denture cream.
16. The cream of claim 1, wherein said phosphate is an alkali
monofluorophosphate.
17. The cream of claim 1, wherein said alkali monofluorophosphate
comprises less of said cream than said bicarbonate on a weight
basis.
18. The cream of claim 17, wherein said alkali monofluorophosphate
is present in a weight ratio to said peroxide of from about 0.1:1
to about 1.6:1.
19. The cream of claim 18, wherein said alkali monofluorophosphate
is present in a weight ratio to said peroxide of from about 0.3:1
to about 0.8:1.
20. The cream of claim 7, wherein said alkali monofluorophosphate
comprises from about 0.05% by weight to about 2.5% by weight of
said cream.
21. The cream of claim 20, wherein said alkali monofluorophosphate
comprises from about 0.4% to about 0.8% by weight of said
cream.
22. A method for cleaning dentures or removable dental prostheses
comprising the step of mechanically scrubbing said dentures or
removable dental prostheses with the cream of claim 1.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to a stabilized denture paste or cream
and to a method for cleaning dentures using a stabilized denture
paste.
2. Description of Related Art
Dentures and other removable full or partial dental prostheses,
like the teeth they replace, require regular cleaning to maintain
the oral health of the wearer. The considerations that go into
designing cleaning compositions for such dental prostheses,
however, differ from considerations in designing cleaning
compositions for teeth.
Teeth are generally cleaned either by brushing with a dentifrice
(or tooth powder) or by rinsing the mouth with a mouthwash.
Dentifrices may contain cleansing ingredients, detergents and
abrasives. Mouthwashes may contain alcohol or other agents to kill
germs in the mouth. An important consideration in formulating a
dentifrice or mouthwash, however, is the organoleptic quality of
the finished formulation. Another important consideration is the
strength of the ingredients used. If the ingredients are too weak,
the dentifrice or mouthwash will not clean properly. If the
ingredients are too strong, the dentifrice or mouthwash could
damage the soft tissues in the mouth.
Dentifrices and mouthwashes may contain other ingredients to
strengthen teeth, such as fluorides, hypersensitivity treatments,
such as potassium nitrate, or remineralization ingredients, such as
hydroxyapatite.
Dental prostheses are typically cleaned either through immersion in
a bath containing a cleansing agent or by brushing with a specially
formulated cream. Immersion has the advantage of offering complete
cleaning, because brushing can miss hard to reach areas of the
dental prosthesis. Brushing, however, offers the advantage of both
mechanical cleaning and chemical cleaning, and many people prefer
brushing with a paste to ensure thorough cleaning of the
prosthesis.
Dentures and dental prostheses, however, are not natural teeth.
Modern dental prostheses are usually made from polymeric materials.
These materials can withstand a high level of cleaning activity,
and prostheses do not require any of the special ingredients, such
as hypersensitivity ingredients, remineralization ingredients and
fluoride treatments, found in dentifrices.
Because of the differing design parameters for denture pastes and
dentifrices, many considerations affecting dentifrice formulations
are not pertinent for denture pastes.
For example, U.S. Pat. No. 5,372,802 discloses a dentifrice that
includes a peroxyacid compound such as hydrogen peroxide, a
fluoride-containing anticaries agent and a zinc compound such as
zinc citrate. The zinc compound inhibits decomposition that
ordinarily would be induced by the presence of fluoride. A denture
paste does not need fluoride, since the acrylic polymer of many
dental prostheses is not strengthened by fluoride.
Despite the general absence of a need for fluoride in treating
dentures and dental prostheses, U.S. Pat. No. 5,736,158 to Quast,
issued Apr. 7, 1998, teaches a denture cleanser tablet or paste for
partial dental prostheses (that do not replace all teeth in the
mouth) containing high levels of fluoride. This fluoride may be
sodium fluoride or sodium monofluorophosphate and may be combined
with a peroxyacid cleansing agent such as calcium peroxide in a
two-layer denture tablet. The fluoride is present at a high level
to impregnate the dental prosthesis during cleaning and to leach
out during use, thereby providing a fluoride treatment for adjacent
natural teeth.
A recent development in dentifrices has been the development of
baking soda and peroxide dentifrices. These dentifrices have been
formulated in "split tube" designs to prevent reactions between
peroxide and baking soda during storage. One example of a split
tube dentifrice is found in U.S. Pat. No. 5,599,525 to Hsu et al.,
issued Feb. 4, 1997. This patent is directed to a split tube
configuration having, among other ingredients, calcium peroxide,
sodium bicarbonate and a fluoride source such as sodium
monofluorophosphate.
Many attempts Wave been made to stabilize the baking soda and
peroxide in a single tube configuration. U.S. Pat. No. 4,837,008,
for example, discloses an aqueous dentifrice containing a peroxide
and/or bicarbonate ingredient. The ingredients are coated to
prevent reaction during storage. A disadvantage to such a
dentifrice is that release of the ingredients for cleaning effect
during use is diminished by the presence of the barrier
coating.
Another approach has been stabilizing the formulation by adopting a
substantially anhydrous system. U.S. Pat. No. 4,897,258 discloses
an anhydrous dentifrice containing calcium peroxide and sodium
bicarbonate. The anhydrous state of the dentifrice prevents
reaction between the ingredients. A disadvantage to such a
dentifrice is that in spite of the anhydrous state of the
dentifrice, limited storage ability is experienced. Anhydrous
systems might also lead to poor dispersion of the ingredients in
the dentifrice itself, and the formulation is expensive compared to
water-based dentifrices. U.S. Pat. No. 4,971,782 discloses an
anhydrous dentifrice containing peroxide and bicarbonate. One
ingredient is coated with a water soluble coating and a peroxide
stabilizer is included in the dentifrice to further enhance storage
stability. In spite of the presence of the stabilizer, the
dentifrice remains deficient in storage stability required for
commercial use.
Attempts to stabilize the ingredients in a water-based dentifrice
include those discussed in U.S. Pat. No. 5,565,190 to Santalucia et
al., issued Oct. 15, 1996, and its divisional patent, U.S. Pat. No.
5,683,680 to Santalucia et al., issued Nov. 4, 1997. These patents
disclose sodium hydroxide or sodium carbonate to stabilize a
dentifrice composition containing peroxide and bicarbonate. U.S.
Pat. No. 5,614,174 to Hsu et al., issued Mar. 25, 1997, is directed
to a dentifrice comprising a peroxide, such as calcium peroxide,
and sodium bicarbonate. The dentifrice may contain a fluoride
source, such as sodium fluoride or sodium monofluorophosphate and
the dentifrice is stabilized by the addition of polyethylene glycol
2000.
Other dentifrices have not recognized the problem. U.S. Pat. No.
4,603,045 to Smigel, issued Jul. 29, 1986, for example, is directed
to a toothpaste adapted for cleaning natural teeth and bonded
composite filling material. The toothpaste contains dicalcium
phosphate, calcium carbonate, magnesium carbonate, sorbitol, corn
starch, cellulose gum, calcium peroxide, sodium perborate, sodium
lauryl sulfoacetate, aluminum hydroxide, saccharinate, flavoring,
alkylparaben, sodium monofluoride phosphate, titanium dioxide and
water. These ingredients must be present in a carefully balanced
combination to achieve the objects of the patent.
U.S. Pat. No. 4,925,655 to Smigel et al., issued May 15, 1990, is
directed to a powder composition soluble in water to form a
mouthwash. The powder contains calcium peroxide, sodium perborate,
sodium bicarbonate, tetrasodium pyrophosphate, sodium lauryl
sulfate, sodium sacchrinate, hydrated silica, sodium benzoate,
citric acid, flavor, potassium carbonate, tea tree oil, sodium
monofluorophosphate, thymol and hexylresorcinol.
U.S. Pat. No. 5,041,280 to Smigel, issued Aug. 20, 1991, is
directed to a toothpaste containing dicalcium phosphate, calcium
carbonate, sodium bicarbonate magnesium carbonate, sorbitol, corn
starch, cellulose gum, calcium peroxide, sodium lauryl
sulfoacetate, aluminum hydroxide, sodium saccharinate, flavoring,
alkylparaben, sodium monofluorophosphate, titanium dioxide and
water.
Despite the recent interest in baking soda and peroxide
dentifrices, denture creams have not generally adopted baking soda
and peroxide. One attractive feature of baking soda and peroxide
dentifrices is that they generate bubbles on use, which gives the
user a pleasant sensation. This benefit is lost in denture creams,
since cleaning is typically done outside the mouth. Also, the
generally stronger cleaning agents used in denture creams can
adversely affect the baking soda and peroxide. Stability of denture
creams containing such ingredients is difficult to achieve.
SUMMARY OF THE INVENTION
The principal object of the present invention therefore is to
provide a denture cream containing baking soda and peroxide
stabilized against degradation, especially thermal degradation,
during storage.
Another object of the invention is to provide a method for cleaning
removable dental prostheses using the denture cream containing
baking soda and peroxide.
It is an advantage of the invention that the baking soda and
peroxide can be stabilized by a dentifrice ingredient, thereby
avoiding the problem of establishing safety information.
Additional objects and advantages of the invention will be set
forth in part in the description that follows, and in part will be
obvious from this description, or may be learned by practice of the
invention. The objects and advantages of the invention may be
realized and attained by means of the instrumentalities and
combinations particularly pointed out in the appended claims.
To achieve the foregoing objects and following the purpose of the
invention, as embodied and broadly described herein, the invention
provides a cream for cleaning removable dental prostheses in
association with mechanical scrubbing, comprising a peroxide, a
bicarbonate and sodium monofluorophosphate.
To further achieve the foregoing objects and by the purpose of the
invention, the invention further provides a method of cleaning a
removable dental prosthesis by scrubbing the removable dental
prosthesis with a cream comprising a peroxide, a bicarbonate and
sodium monofluorophosphate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the presently preferred
embodiments of the invention.
Peroxide compounds can become unstable at elevated temperatures.
Dentifrice and denture cream formulations containing peroxides can
lose peroxide activity if stored for even limited time at
temperatures greater than about 100.degree. F. Stabilizing the
peroxide can have a positive impact on denture creams, especially
for formulations sold in warm regions.
Denture creams may contain peroxide compounds as cleaning agents,
either alone or in combination with other peroxides or other
cleaning agents. Preferred peroxides useful in the invention
include, but are not limited to, peroxide acids such as hydrogen
peroxide, and monovalent and divalent peroxide salts, such as
sodium and calcium peroxide. Preferred peroxides include divalent
salts such as calcium peroxide. The peroxide may comprise any
amount in the cream to accomplish the desired cleaning effect.
Generally, however, the peroxide comprises from about 0.1% to about
10% by weight of the cream formulation, preferably from about 0.25%
to about 5% by weight and more preferably from about 0.5% to about
2.5% by weight of the denture cream.
The peroxide in the denture cream is stabilized against degradation
during shipping and storage by a combination of bicarbonate and
monofluorophosphate. This discovery is surprising, since both the
bicarbonate and the monofluorophosphate are needed to stabilize the
peroxide. If the monofluorophosphate is removed from a formulation
otherwise in accord with the invention, then the calcium peroxide
decomposes and loses its efficacy as a cleaning and whitening
agent. The same holds true if the bicarbonate is absent from a
formulation otherwise according to the invention.
The bicarbonate may be any known bicarbonate useful in denture
creams, including, but not limited to, potassium bicarbonate and
sodium bicarbonate. Sodium bicarbonate, however, is preferred for
cost and supply reasons. Preferably, the bicarbonate comprises more
of the denture cream formulation than the peroxide on a weight
basis. More preferably, the bicarbonate will be present in a weight
ratio to the peroxide from about 2:1 to about 10:1, and most
preferably from about 2:1 to about 5:1. Thus, if the peroxide is
within its preferred range of from about 0.5% by weight to about
2.5% by weight of the denture cream, the bicarbonate will comprise
from about 1% by weight to about 25% by weight of the denture
cream, more preferably from about 1% by weight to about 10% by
weight of the denture cream and even more preferably about 5% by
weight of the denture cream.
The monofluorophosphate is preferably sodium monofluorophosphate,
although other known cations and ligands, especially alkali
cations, may be associated with the monofluorophosphate. The
monofluorophosphate preferably comprises less of the denture cream
than the bicarbonate and the peroxide on a weight basis. Preferably
the monofluorophosphate is present in a weight ratio to the
peroxide of from about 0.1:1 to about 1.6:1, and more preferably
from about 0.3:1 to about 0.8:1. If the peroxide is present in the
denture cream in its preferred range of from about 0.5% by weight
to about 2.5% by weight of the denture cream, the
monofluorophosphate preferably comprises from about 0.4% to about
0.8% by weight of the denture cream.
Although sodium monofluorophosphate is the most preferred
stabilizing agent, other phosphates such as tetrapotassium
pyrophosphate, tetrasodium pyrophosphate, and trisodium phosphate
may also be used to stabilize the peroxide in the formulations.
The denture cleanser formulation may also contain additional
ingredients, including water, glycerin, humectants such as
propylene glycol and polyethylene glycol, abrasives, such as
silicon dioxide and hydrated silica, detergents and surfactants
such as sodium lauryl sulfate, thickeners, such as carboxymethyl
cellulose, and whiteners such as titanium dioxide.
Since the denture cream can leave a residue on the dentures or
dental prosthesis after cleaning, the denture cream may also
contain sweeteners and flavoring agents, including peppermint oil,
menthol, saccharin, and anethole.
The purpose of the following examples is to illustrate some
embodiments and principles of the invention, without implying a
limitation on the scope or spirit of the invention.
EXAMPLES 1 AND 2
Two denture creams were prepared having the formulations set out in
Table 1. In each instance, 60% of the required amount of water was
added to a mixing tank, along with the propylene glycol and 65% of
the glycerin. The sodium monofluorophosphate was added to the
mixing tank and mixed until dissolved. The sodium saccharin,
titanium dioxide, and sodium bicarbonate were then added and mixed
to a uniform blend. The polyethylene glycol was then added and
mixing continued. The silicon dioxide and hydrated silica were
added and mixing continued. At this point, the mixture thickened,
so 25% of the water was added to the mixing tank and the resulting
blend was
mixed under high shear. The carboxymethyl cellulose was separately
dispersed in the remaining glycerin and this mixture was added to
the mixing tank while mixing continued for an additional twenty
(20) minutes until gel formation. The flavors and sweeteners were
added to the mixing tank along with sodium lauryl sulfate. After
the flavors had been mixed for twenty (20) minutes, the remaining
water and calcium peroxide were added and mixed thoroughly for five
minutes. The resulting cream was filled into suitable tubes.
EXAMPLE 3
A comparison of the stabilizing effect of various combinations on
the peroxide was made by making the denture cream of Examples 1 and
2 using various compounds in place of the sodium
monofluorophosphate. The active oxygen in the denture cream was
measured after the denture paste was prepared and the denture
creams were then stored at 50.degree. C. The active oxygen was
measured at one, two and four weeks after storage, and the results
are reported in Table 2. These results show that sodium
monofluorophosphate is an effective agent and that the other
phosphates, while not as effective as sodium monofluorophosphate,
also provided some stabilizing effect.
The purpose of the above description is to illustrate some
embodiments of the present invention without implying a limitation.
It will be apparent to those skilled in the art that various
modifications and variations may be made in the apparatus or
procedure of the invention without departing from the scope or
spirit of the invention.
TABLE 1 ______________________________________ Formulations of
Examples 1 and 2 Example 1 Example 2 Ingredient (Wt. %) (Wt. %)
______________________________________ Calcium Peroxide 0.50 0.50
Purified water 12.00 12.00 Glycerin 21.00 20.00 Propylene Glycol
27.00 26.00 Sodium Monofluorophosphate 0.40 0.40 Sodium Bicarbonate
5.00 5.00 Silicon Dioxide 2.00 4.00 Sodium Saccharin 0.30 0.30
Titanium Dioxide 1.00 1.00 Hydrated Silica 17.00 17.00 Polyethylene
Glycol 600 10.00 10.00 Carboxymethyl cellulose 12M31XP 0.60 0.60
Sodium Lauryl Sulfate 2.00 2.00 Peppermint Oil 0.82 0.78 Menthol
0.25 0.42 Anethole 0.13 0.00 Total 100.00 100.00
______________________________________
TABLE 2 ______________________________________ Active Oxygen Loss
from Example 3 % Loss % Loss % Loss Initial Active after after
after Active Ingredient Oxygen 1 week 2 weeks 4 weeks
______________________________________ 0.4% sodium 0.0765% 2.2%
6.1% 21.3% monofluorophosphate 0.12% sodium fluoride 0.075% 62.8%
88.3% 89.5% 0.9% tetrapotassium 0.072% 7.9% 8.7% 27% pyrophosphate
0.45% trisodium 0.665% 20.0% 22.6% 40.7% phosphate
______________________________________
* * * * *